This invention relates to a dielectric ceramic composition and, more particularly, an improved dielectric ceramic composition useful as a dielectric material for monolithic ceramic capacitors and the like. 2. Description of the Prior Art
As a dielectric ceramic composition for monolithic ceramic capacitors, there have widely been used those comprising, as a main constituent, barium titanate (BaTiO.sub.3) or titanium dioxide (TiO.sub.2). In the sequence of manufacture, monolithic ceramic capacitors are occasionally trimmed by laser beams to adjust its capacitance so that the dielectric ceramic compositions therefor are required to have such a property that they are scarcely affected by application of laser beam. However, the above ceramic compositions have such a disadvantage that the insulation resistance thereof is considerably decreased by the application of laser beams, thus making it difficult to manufacturing monolithic ceramic capacitors with desired characteristics.
In order to solve this problem, it is considered to be preferred to use alumina ceramics since the insulation resistance thereof is never decreased even by the application of laser beam. However, the alumina ceramics have a high sintering temperature of not less than 1600.degree. C., thus making it impossible to manufacture monolithic ceramic capacitors even if noble metals such as Pd and Pt, which have a high melting point, are used as a material for internal electrodes.